Device for folding sheet-metal plates



(N0 Model.) 2 Sheets-Sheet 1.

' W. G. HYNDMAN, DEVICE FOR FOLDING SHEET METAL PLATES.

No. 422,944. Patented Mar. 11, 1890.

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2 N A M D N Y H G W DEVICE FOR FOLDING SHEET METAL PLATES. No. 422,944,

Patented Mar. 11,1890.

N. PETERS, Pholo-Lithngmpher. Washington. D. Q

UNITED STATES PATENT OFFICE.

\VILLIAM GRAVES IIYNDMAN, OF CINCINNATI, OIIIO.

DEVICE FOR FOLDING SHEET-METAL PLATES.

SPECIFICATION forming part of Letters Patent No. 422,944., dated March11, 1890.

Application filed December 26, 1889. Serial No. 335,008. (No model.)

To all whom it may concern:

Be it known that .I, \VILLIAM GRAVES HYNDMAN, a citizen of the UnitedStates, residing at Cincinnati, in the county of Hamilton and State ofOhio, have invented certain new and useful Improvements in Devices forFolding Sheet-\lctal Plates; and I do hereby declare that the followingis a full, clear, and exact description of the same, reference being hadto the annexed drawings, making a part of this specification, and to thelet-- ters of reference marked thereon.

This invention relates to certain new and useful improvements inmachines for folding or bending sheet-metal plates; and it has for itsobject, among others, to provide a machine of this character which,after making the fold, will be turned back into its original positionready for more work, releasing itself from the metal sheet or plate,clearing the foldmade without moving the sheet or plate and withoutturning the same.

It aims also in novel features of construction, which will behereinafter described more fully, shown in the drawings, and thenparticularly pointed out in the appended claims.

The invention is clearly illustrated in the accompanying drawings,which, with the let ters of reference marked thereon, form a part ofthis specification, and in which- Figure l is a top plan of my improvedmachine. Fig. 2 is a side elevation or longitudinal section through thesame, with the parts shown in full lines in the position they assumebefore bending the sheet or plate. Fig. 3 is a like view showing in fulllines the position the parts assume after bending the sheet or plate.

Like letters of reference indicate like parts throughout the severalviews.

Referring now to the details of the draw ings by letter, A designates asuitable bedplate for supporting the various parts of the machine. Thismay be of any suitable ma 'terial and of a size adapted for the purpose.

Upon this bed-plate at one side is a raised bed A, upon which the sheetor plate is designed to rest while being bent. It is provided upon.

bed, near the longitudinal center thereof, are

the raised stops B, the object of which will journaled the ends of thetrunnions 1), formed upon curved lines, as shown at c, and which carrythe parallel arms D, the outer ends of which are connected by across-bar E, pref erably round andwhich serves as a handle by which thedevice is operated. The trunnions are preferably formed of a hollowpipe, to which the parallel arms are secured by a screw-threadengagement, so that they may be readily connected or detached when desired, and the end of the curved portionforms a convenient stop for thesliding bracket hereinafter described.

F is the bending-bar, provided along its acting edge with a recess (1,to receive and hold the edge of the sheet or plate to be bent, as shownbest in Figs. 2 and 3. preferably formed between the bar and a metalplate secured to the upper face thereof, as shown; but it may otherwisebe formed, if desired. Upon the ends of this bending bar are cast orrigidly secured the brackets G, in apertures in the ears of which thepar allel arms D are designed to loosely Work, the said arms beingprovided between the ears with a stop-pin e, as shownin Fig. 1.

H are coiled springs around the arms D, between the outer ears on thebrackets G and a retaining pin f on the said arms.

I are lugs on the crossbar E, one near each end thereof, and J arecorresponding lugs on the bending-bar F. K are toggledevers pivotallyconnecting the said lugs, and one arm of the toggle is made adjustableby means of a turn-buckle L.

M are cam plates on the upper face of the bed A, as shown in all thefigures of the drawings, and the object of which will soon appear.

In operation the parts are normally in the position in which they areshown in Fig. 1 and in full. lines in Fig. 2. The sheet or plate N to bebent is then placed. upon the raised bed with its edge entered in therecess in the bendingbar, as shown in Fig. 2. The

togglelevers are at this time straightened. The bending-bar is thenbrought over into This recess is the position shown by full lines inFig. 3, the

metal being bent as indicated in said Fig. 3. In the further movement ofthe parts the toggles come in contact with the tops of the stops B, andthe toggles are thus raised, allowing the springs to draw thebending-bar away from the bent end of the sheet or plate. The parts arethen thrown over into their normal position, and when thus thrown thetoggle-levers come in contact at their joints with the cam-plates M onthe bed-plate, as shown by dotted lines in Fig. 3, and the toggles arestraightened in the further movement of the parts and the springs on thearms D are compressed. The stop-pin e limits the movement of the arms inthe direction of their length.

It will thus be seen that the device is antomatic in its action. As soonas the sheet is bent the toggles are raised, the springs draw thebendingbar away from the bent sheet, and as the parts are thrown backaway from the sheet the toggles are again automatically straightenedready for work, and, the bent sheet having been removed and anotherplaced in position, the operation may be repeated.

Various modifications in detail may be resorted towithout departing fromthe spirit of the invention.

W'hatI claim as new is 1. The combination, with the bending-bar and theoperating-arms, of toggle-levers conneeting the bar and arms and stopsfor breaking the levers after bending the metal, as set forth.

2. The combination, with the bendingbar bar and arms and stops forautomatically raising and straightening the levers, as set forth.

4. The combination, with the bending-bar and the spring-actuated armsconnected therewith, of the toggle-levers pivotally connected to the barand arms, the stops B, engaging said levers to break them after formingthe fold, and a cam arranged to straighten the toggles as the parts arethrown into their normal position, as set forth.

In testimony that I claim the above I have hereunto subscribed my namein the presence of two witnesses.

7M. GRAVES HYNDMAN.

Witnesses:

OLIVER 13. J ONES, J OHN J. SULLIVAN.

